The invention concerns a device for producing interlaced knots in a multifilament thread.
A generic device for producing interlaced knots in a multifilament thread is known from DE 41 40 469 A1. It is generally known that with the production of multifilament threads, the coherence of the individual filament strands in the threads is obtained by means of so-called interlaced knots. Interlaced knots of this type are produced by means of pressurized air treatment of the threads. Depending on the type of threads, and the process, the desired number of interlaced knots for each unit of length as well as the stability of the interlaced knots may be subject to different demands. Particularly with the production of carpet yarns, in which further processing occurs immediately following a melt spinning process, a high degree of knot stability and a relatively high number of interlaced knots for each unit of length of the thread is desired.
In order to obtain, in particular, a high number of interlaced knots at higher thread feed speeds, the generic device includes a rotating nozzle ring, which acts together with a stationary stator. The nozzle ring includes a thread guide groove on its circumference. On the groove base numerous nozzle bores open, which are uniformly distributed over the circumference. The nozzle bores radially penetrate the nozzle ring, from the guide groove to an inner pilot diameter, which follows the circumference of the stator. The stator includes an internal pressure chamber, which is connected by means of a chamber aperture formed on the circumference of the stator. The chamber aperture on the stator, as well as the nozzle bores in the nozzle ring lie in a plane, such that when the nozzle ring is rotated, the nozzle bores are guided successively to the chamber aperture. In this manner, by means of the rotation of the nozzle ring, an air quantity is determined, which is blown from the chamber aperture, via the nozzle bore, into the guide groove, for the purpose of swirling the multifilament threads. As a result, each of the nozzle bores generates a pressure pulse within the guide groove. For this it is necessary that aside from a typical swirling of the filament strands, the quantity of air acting on the threads is sufficient to produce knot-like interlacings, which exhibit sufficient dimensional stability. As such, it has been observed that with smaller air quantities, and accordingly smaller pressure pulses, only swirling is obtained, and no interlaced knots are produced.